Hydrodynamic vortex aspiration catheter

ABSTRACT

An actuated telescoping system for navigation within a vascular lumen and thrombectomy of a thrombus. The system includes a tubular catheter member having an open distal end defining a catheter lumen, a vacuum source, a rotational drive system, a flexible shaft having a channel coupled to the rotational drive system for rotational movement in response thereto, and an optional guidewire selectively inserted at least partially within the flexible shaft. The flexible shaft is at least partially disposed within the tubular catheter member configured for uncoupled rotational and translational motion therein and to optionally define a corkscrew motion in response to rotational driving force by the drive system that results in formation of hydrodynamic vortices within the catheter lumen. The telescoping system can be capable of reversibly transitioning between navigation and thrombectomy modes by differentially disposing and actuating the components and enable faster, more efficient and simpler removal of thromboembolic material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No.PCT/US2019/026737, filed on Apr. 10, 2019, which is acontinuation-in-part application of U.S. patent application Ser. No.16/156,519, filed Oct. 10, 2018, which is a continuation-in-partapplication of PCT International Application No. PCT/US2018/026831,filed on Apr. 10, 2018, which claims the benefit of U.S. ProvisionalApplication No. 62/483,580, filed on Apr. 10, 2017. This application isalso a continuation-in-part of U.S. patent application Ser. No.16/156,519, filed Oct. 10, 2018. The entire disclosures of each of theabove applications are incorporated herein by reference.

FIELD

The present disclosure relates to catheters and, more particularly,relates to an aspiration catheter augmented by hydrodynamic vorticesthat are generated by high-speed rotation of a flexible shaft.

BACKGROUND AND SUMMARY

This section provides background information related to the presentdisclosure, which is not necessarily prior art. This section provides ageneral summary of the disclosure, and is not a comprehensive disclosureof its full scope or all of its features.

Thrombosis is the formation of a blood clot inside a blood vessel,obstructing the flow of blood through the circulatory system. Theformation of a thrombus can occur within the heart or any artery or veinin the body, leading to a myriad of medical problems such as myocardialinfarction, stroke, pulmonary embolism, and deep venous thrombosis.Rapid thrombectomy is frequently needed in cases of 1) obstruction ofarteries of delicate organs, such as the heart or the brain; 2) largeclots interrupting blood flow in major vessels or causing severesymptoms; or 3) when systemic delivery of the drugs is too risky.

Multiple thrombectomy devices have emerged in the last decades. However,these devices continue to be largely ineffective with large clot burden,“organized” (i.e. thick) clots, and clots extending from large to smallvessels, and many such devices cause distal embolization of clots andvascular damage as they dispose the cutting or macerating mechanismdirectly into the vascular lumen. In addition, devices are generallyspecific for a certain lumen size, which translates to the need ofcombining multiple sizes and types of devices in the same procedure.Mechanical thrombectomy in stroke presents additional challenges basedon the tortuosity of vessel and the delicate nature of vessel walls. Inthis regard, mechanical thrombectomy mechanisms that have beensuccessfully used in the peripheral vasculature to remove clots, some ofwhich are described below, are too bulky and stiff for navigating thecomplex cerebral artery geometries, release many clot particlesdownstream leading to microvascular occlusion, or are too abrasive fordelicate brain arterial walls.

Modification of catheter shape has been suggested or disclosed in theprior art to enhance aspiration of intravascular clots. In U.S. Pat. No.8,075,510 to Aklog et al., a suction cannula is described with a distalend that is deployable to expand from a first diameter to a relativelylarger second diameter with a funnel shape. The differential diameter isbelieved to induce a laminar flow circumferentially along the interiorsurface of the funnel to generate a vortex flow into the distal end ofsuction cannula. In the presence of a vortex flow, such a flow can actto direct the undesirable material toward the distal end to allow thematerial to subsequently be pulled into the distal end by suctioning.

Other systems and methods have been disclosed in the prior art toachieve thrombectomy based on waterjet thrombectomy catheters. Thecatheters described may have proximal-to-distal waterjet flow, such asU.S. Pat. No. 5,135,482 to Neracher, or distal-to-proximal-directedwaterjet flow past a window, orifice or gap at the distal end of thecatheter, re-entering the catheter and pushing flow through anevacuation lumen, such as in U.S. Pat. No. 6,676,637 to Bonnette et al.The Bonnette Patent describes a dual catheter assembly with the innertube having a high-pressure lumen with a distally located jet emanatorhaving one or more rearwardly directed orifices for directing one ormore jets of saline toward the distal end of a flow director whichfragments and drags clots into the outer larger catheter.

Catheter-based instruments with different macerating mechanisms havebeen suggested or disclosed in the prior art for to fragment clots forthrombectomy in the vascular lumen with revascularization of arteriesand veins. With these devices, the clot is broken into smaller pieces,most of which migrate further downstream, decreasing the centralobstruction. U.S. Pat. No. 5,876,414 to Straub discloses a catheter forclearing a vessel composed by a rotary drive mechanism that rotates ahelical shaped cutting tool. As the rotor rotates, dual cutting slotsengage and sever the material along the vessel wall. U.S. Pat. No.6,238,405 to Findlay discloses another catheter device for removingmaterial having a rotatable screw thread distal end adjacent a shearingmember also near the distal end. By application of the “Archimedes”screw action, in combination with vacuum, thrombus is drawn into thedevice in order to be macerated by shear and removed. U.S. Pat. No.5,695,507 to Auth describes a helically wound coil wire deliveredthrough a catheter with or without vacuum that is disposed outside thecatheter within the clot mass in the arterial lumen and rotated at apreferable speed of 500 to 6000 rpm to cause fibrin to be wound aroundthe shaft. As the fibrin fibers follow the rotating core, they areeventually stripped away from the clot, which loses its structuralnetwork. This leads to release of red blood cells back into thecirculatory system, since the insoluble material is retained on the corewire for later extraction from the body. U.S. Pat. No. 6,090,118discloses a mechanical thrombectomy device with a wire that extendsdistal to a catheter and is rotated to create a standing wave tobreak-up or macerate thrombus. U.S. Patent Publication No. 2002/0173812discloses a thrombectomy wire that has a sinuous shape at its distal endand is contained within a sheath in a substantially straightnon-deployed position. When the sheath is retracted, the distal portionof the wire is exposed to enable the wire to return to its non-linearsinuous configuration. Actuation of the motor causes rotational movementof the wire, creating a wave pattern, to macerate thrombus. Othersinuous or s-shaped rotatory wires to disrupt clots are disclosed inU.S. Pat. Nos. 9,282,992 and 6,926,725, and U.S. Patent ApplicationPublication Nos. 2004/0006306, 2017/0007290, and 2017/0007290. Theabovementioned devices are not intended to pass through tortuouspathways found in the fragile brain vessels as they would release clotmaterial downstream leading to strokes, or the actuation of themacerating mechanism disposed directly in the vascular lumen would leadto vascular damage of delicate vessels.

Another rotary thrombectomy mechanism is disclosed in US 2016/0166266 byNita with a rotating longitudinal element with a shaped tip disposedwithin an aspiration catheter. This rotating element is advanced toposition after the aspiration catheter has reached the target with thehelp of ancillary “support elements”, such as intermediate catheters. Inorder to advance the rotating element to position near the end of thecatheter through complex anatomy, it must have sufficient stiffness tobe pushed without kinking or looping. In addition, the rotationalelement is constructed with sufficient stiffness to serve as a clotmacerating tool. The required stiffness of the rotatory elements in thisprior art, along with the inability to be co-axially navigated over aninner guidewire, would preclude its use for atraumatic navigation withinthe vasculature beyond the tip of the aspiration catheter. To completelyprevent the distal tip of the rotational member from being exposedoutside the aspiration catheter, the rotating element includes a stopperby design. Additionally, the required stiffness of the rotary elementcreates large radial forces against the inner wall of the catheter,leading to high friction and rapid wear of the catheter. This isespecially relevant if the rotating element acquires corkscrew motionupon high speed rotation, requiring the mechanism to operate belowtorque load needed to generate hydrodynamic vortices. The prior art doesnot disclose a stand-alone device suitable for both navigation intonarrow and highly tortuous vasculature and the ability to clearocclusive material by rotatory-induced hydrodynamic vortices. Such atechnology would be challenging to develop as the features needed forsafe intravascular navigation are generally contraposed to the featuresneeded for efficient clot removal.

The present teachings overcome the shortcomings of the prior art tocreate a device for both atraumatic navigation into tortuous vasculatureand mechanical thrombectomy. According to the present teachings, thesame components that enable safe and efficient intravascular navigationprovide clot removal, leading to highly efficient and effectiveinterventions. This multimodal thrombectomy device design for navigationand thrombectomy is achieved by the invention of an actuated telescopingsystem that allows coaxial and steerable advancement of the device totarget, and the generation of forces leading to rapid and effectivethrombectomy. The device contains a flexible navigation system that canbe atraumatically deployed within complex vasculature with or without aguidewire. This navigation system provides “scaffolding” (by itself, orbased on the coupled stiffness of the guidewire inside the navigationelement's lumen and the navigation element itself, or by the coupledstiffness of additional intermediate catheter(s) that also telescope tocreate a coupled system) to enable the coaxial advancement of one ormore larger diameter aspiration catheters to challenging targets. Thesenavigation elements can subsequently be shielded within a catheter andactuated as a thrombectomy system in cooperation with external vacuum togenerate hydrodynamic vortices and corkscrew movements for clot removal.In some embodiments, the telescoping system composed by guidewire, anavigation/thrombectomy rotational element (henceforth named “shaft”)and a catheter collectively constitute a tri-axial system. This systemis well suited to navigate highly tortuous, but delicate, anatomy, butat the same time provide the needed scaffolding to allow the advancementof big bore suction catheters, as it is frequently needed to remove clotin large vessel occlusion in stroke.

In some embodiments, the telescope system can also be constructed by atapered and steerable shaft that can be disposed within the vascularlumen without the co-axial use of a guidewire. In this embodiment, theshaft can be guided and advanced into the vascularity and providescaffolding for catheter advancement to target during navigation mode.Upon proximity with the occluding material, the shaft can be actuatedfacilitating clot removal. This bi-axial telescoping system can enablesignificant downscaling to reach smaller vessels, such as distalcerebral arteries, while maintaining maximum vacuum and enabling thegeneration of thrombectomy forces upon high speed rotation of thesteerable shaft.

In some embodiments, the tri-axial telescoping system can becomplemented by the addition of one (i.e. tetra-axial system) or moretelescoping catheters for enhanced navigation and thrombectomy. Theadditional telescoping catheter (henceforth named “sleeve”) can bedisposed co-axially between the shaft and the suction catheter and bedesigned to have uncoupled movements with the other components of thetelescoping system. During navigation mode, the sleeve can be disposedat least partially over the shaft to minimize kinking and looping of theflexible shaft upon forward advancement into the vasculature. The sleevecan also enhance the scaffolding function of the shaft while decreasingthe shelf (gap between shaft and catheter) to advance a large boresuction catheter co-axially. In addition, during navigation mode thesleeve can be disposed over the shaft at least partially to shieldthrombectomy enhancing features of the shaft that would be unsafe to bedirectly exposed to the vascular surfaces, or to provide enoughstiffness to the advancing shaft and guidewire to penetrate theobstructing clot mass and allow the catheter to enter the clot massrather than be pushed back or aside between the clot and the artery.During thrombectomy, the sleeve can be retracted to unsheathethrombectomy enhancing features of the shaft, unleash the highlyflexible shaft to generate thrombectomy forces upon high speed rotation,and increase the available cross-sectional lumen to facilitate clotengaging and removal with maximal vacuum power. The sleeve can be alsoadvanced over the shaft to unload the shaft of clot debris. In addition,the sleeve can provide a channel to deliver solutions to the cathetertip before, during and/or after the procedure. None of these elementsneed to be completely removed from the system in order for the system tooperate correctly, allowing rapid transitioning betweennavigation/thrombectomy modality and function.

In some embodiments, the shaft can be shorter than the telescopingsystem and disposed distally within the aspiration catheter. The shaftcan be connected to one or more wires controlled by the actuator modulethat are extending inside, outside or within the wall of the aspirationcatheter. The wire can be advanced towards the catheter, which causesthe shaft to emerge from the catheter and advance into the vascularlumen as a navigation element (this can be supported by the use of aco-axial guidewire if needed inside the shaft). In this position, theshaft provides scaffolding for catheter advancement to target duringnavigation mode. After advancing the catheter to target, the shaft canbe retracted into the catheter lumen by withdrawing the wire and can beactuated to generate vortices forces for thrombectomy. The actuation ofthe shaft can be driven by rotation of the wire through a system ofgears and belts or alike or through injection of pressurized solutioninto a water wheel or alike. The wire adjusting the position of theshaft can be a monofilament, coil or braid. The telescope system in thisembodiment maximize vacuum efficiency and flow by reducing the extend ofshaft disposed within the suction catheter, and optimized torquetransmission while reducing wear and tear by disposing a wire, ratherthan a shaft, in the segments of the telescope system traversingtortuous anatomy.

According to the teachings of the present invention, this technologyprovides an integrated mechanism for enhanced navigation into the targetvessel and complete recanalization by anchoring and removing theobstructive thrombus by innovative thrombectomy mechanisms heredisclosed. Such a system capable of reversibly transitioning betweennavigation and thrombectomy modes by differentially disposing andactuating multiple telescoping components would enable faster, moreefficient and simpler removal of thromboembolic material.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is an exploded perspective view illustrating an aspirationcatheter system according to the principles of the present teachings.

FIG. 2 is a side view of the aspiration catheter system according to theprinciples of the present teachings with the guidewire installed and thenavigation element extended beyond the distal tip of the aspirationcatheter.

FIG. 3 is a side view of the aspiration catheter system according to theprinciples of the present teachings with the guidewire removed and thenavigation element retracted at the distal opening or within theaspiration catheter.

FIG. 4 is a cross-sectional view illustrating the aspiration cathetersystem according to the principles of the present teachings.

FIG. 5 is a cross-sectional view illustrating the telescoping hypotubeseal according to the principles of the present teachings.

FIG. 6 is a cross-sectional view illustrating the gear set according tothe principles of the present teachings.

FIGS. 7A-7D are schematic end views illustrating a flexible shaftdisposed within a catheter according to the principles of the presentteachings.

FIG. 8A is a perspective view of a flexible shaft according to someembodiments of the present teachings.

FIG. 8B is a side view of the flexible shaft of FIG. 8A disposed in acatheter according to some embodiments of the present teachings.

FIGS. 8C-8D are schematic cross-sectional views illustrating varyingprofiles of the flexible shaft.

FIGS. 9A-9F are perspective views and end views of a flexible shafthaving hydraulic inducing features and/or eccentric features accordingto some embodiments of the present teachings.

FIGS. 10A-10D are perspective views and end views of a flexible shafthaving eccentric features according to some embodiments of the presentteachings.

FIGS. 11A-11F are perspective views and end views of shaft tips for usewith the flexible shaft according to some embodiments of the presentteachings.

FIG. 12 is a partial cross-sectional view of the catheter and flexibleshaft according to some embodiments of the present teachings.

FIGS. 13A-13C are partial cross-sectional views of the catheter andflexible shaft having fluid and/or guidewire delivery systems accordingto some embodiments of the present teachings.

FIGS. 14A-14B are a partial cross-sectional views of the catheter andflexible shaft illustrating the motion responses of the catheter andflexible shaft during thrombectomy according to some embodiments of thepresent teachings.

FIGS. 15A-15D are schematic end views illustrating motion of theflexible shaft disposed within a catheter according to the principles ofthe present teachings.

FIG. 16A is a graph illustrating the orbital translation of the flexibleshaft within the catheter during thrombectomy.

FIG. 16B is a pressure gradient graph illustrating the pressure gradientcreated within the catheter during thrombectomy.

FIGS. 17A-17G are schematic views illustrating the method according tosome embodiments of the present teachings.

FIGS. 18A-18D are schematic views illustrating the method according tosome embodiments of the present teachings.

FIGS. 19A-19G are partial cross-sectional views of the catheter andflexible shaft illustrating the corkscrew or helical motion of theflexible shaft during thrombectomy according to some embodiments of thepresent teachings.

FIG. 20A is an exploded perspective view illustrating an aspirationcatheter system according to the principles of the present teachingshaving a sleeve and sleeve slider in a retracted position.

FIG. 20B is a partial cross-sectional view of the catheter, the sleeve,and the flexible shaft in the retracted position of FIG. 20A.

FIG. 21A is an exploded perspective view illustrating the aspirationcatheter system of FIG. 20A according to the principles of the presentteachings having the sleeve and guidewire in an extended position.

FIG. 21B is a partial perspective view of the catheter, the sleeve, andthe guidewire in the extended position of FIG. 21A.

FIG. 22A is an exploded perspective view illustrating the aspirationcatheter system of FIG. 20A according to the principles of the presentteachings having the sleeve, the flexible shaft, and guidewire in anextended position.

FIG. 22B is a partial perspective view of the catheter, the sleeve, theflexible shaft, and the guidewire in the extended position of FIG. 22A.

FIG. 23 is a cross-sectional view illustrating the aspiration cathetersystem of FIG. 20A according to the principles of the present teachings.

FIG. 24 is a partial enlarged cross-sectional view illustrating theaspiration catheter system of FIG. 20A illustrating a fluid port.

FIG. 25A is a side view illustrating a sheathed deployable elementdisposed on the flexible shaft and contained with the sleeve.

FIG. 25B is a side view illustrating an unsheathed deployable elementdisposed on the flexible shaft and extending from the sleeve.

FIGS. 26A-26D are perspective views and end views of a shaft tip for usewith the flexible shaft according to some embodiments of the presentteachings.

FIG. 27A is a perspective view of the flexible shaft having an enhancingfeature deployable in response to high speed rotation of the flexibleshaft illustrated in an undeployed position.

FIG. 27B is an end view of the flexible shaft and enhancing feature ofFIG. 27A.

FIG. 28A is a perspective view of the flexible shaft having theenhancing feature deployable in response to high speed rotation of theflexible shaft illustrated in a deployed position.

FIG. 28B is an end view of the flexible shaft and enhancing feature ofFIG. 28A.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings. Example embodiments are provided so that thisdisclosure will be thorough, and will fully convey the scope to thosewho are skilled in the art. Numerous specific details are set forth suchas examples of specific components, devices, and methods, to provide athorough understanding of embodiments of the present disclosure. It willbe apparent to those skilled in the art that specific details need notbe employed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer, or section discussed below can be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

According to the principles of the present teachings, an aspirationcatheter system 10 implementing hydrodynamic vortices generated byrotation of a flexible shaft 12 is provided having an advantageousconstruction and method of use that is particularly configured togenerate hydraulic forces and translational movements to engage,pull-in, fragment, and/or remove clot 100 or other obstructing material(collectively referred to herein as “clot 100”) in cavities, organs orlumens. As will be described in detail herein, flexible shaft 12 rotatesat a high speed with uncoupled rotation of the shaft and translationalmotion within at least an area defined by the internal wall of catheter14 within which it is disposed. Generally, flexible shaft 12 rotates atspeeds greater than 10,000 RPM during thrombectomy mode. FIG. 16Aillustrates the pressure field on a cross section of the catheter withflexible shaft 12 rotating at 90,000 RPM from the computational fluiddynamics modelling. The rotating flexible shaft 12 drives the fluidsurrounding it to rotate in the same direction and creates a pressuregradient across the gap between shaft 12 and catheter wall 17. Thispressure gradient pushes flexible shaft 12 to do orbital translationinside catheter 14. This orbital translational motion, together with thehydrodynamic force and phase lag of mass elements along the length ofthe shaft 12, induces vortex capable of causing the flexible shaft 12 toactuate in corkscrew fashion at least partially within the catheter 14.In some embodiments, the rotation of flexible shaft 12 is not directlycorrelated with the translational motion of flexible shaft 12 insidecatheter 14. This translational motion of the rotating flexible shaft 12can be normal, parallel, or any combination thereof with respect to aplane which is normal to the center axis of containment catheter 14. Insome embodiments, aspiration catheter system 10 comprises a vacuumsource fluidly coupled to catheter 14.

With particular reference to FIG. 1, in some embodiments, aspirationcatheter system 10 comprises flexible shaft 12 disposed within catheter14. Catheter 14 can be selectively coupled to a catheter connectionpoint 16. Catheter connection point 16 enables catheter 14 to beselectively removed, replaced, detached, or otherwise manipulatedrelative to the remaining portions of aspiration catheter system 10. Insome embodiments, catheter connection point 16 permits independentrotation of catheter 14 with regard to the rest of aspiration cathetersystem 10 to improve navigation ability.

Catheter connection point 16 can be attached or integrally formed with avacuum port assembly 18 having a vacuum port 20 and an adjustablecatheter sliding lock 22. Vacuum port 20 is operably coupled to a vacuumsource 24 for exerting a vacuum pressure within catheter 14 and at adistal end 15 of catheter 14 to suck clot 100 into distal end 15 ofcatheter 14 and into vacuum port 20 in accordance with the principles ofthe present teachings. Vacuum port 20 can be “Y” shaped, “L” shaped, “T”shaped or “tri-Y” shaped. In some embodiments, the vacuum pressure isdelivered in dynamic fashion by changing pressures at differentfrequencies between approximately 0.5 Hz and 1000 Hz with magnitudebetween approximately −100 kPa to −5 kPa on a gauge pressure scale. Insome embodiments, the vacuum pressure is constant.

In some embodiments, catheter sliding lock 22 enables customizablespacing of flexible shaft 12 and the distal end 15 of catheter 14. Insome embodiments, catheter sliding lock 22 can be adjusted such that adistal end 13 of flexible shaft 12 is within a maximal clot busting zonewithout protruding beyond it. In some embodiments, distal end 13 offlexible shaft 12 does not extend beyond distal end 15 of catheter 14.This is particularly useful in applications where contact of flexibleshaft 12 and the associated tissue is to be avoided. In someembodiments, distal end 13 of flexible shaft 12 extends beyond distalend 15 of catheter 14. This is particularly useful in applications wherecontact of flexible shaft 12 and the associated tissue is desired.

In some embodiments, vacuum port assembly 18 is coupled to telescopinghypotubes 26 that permit a flexible shaft advancement slider 28 to moveflexible shaft 12 along the longitudinal axis of catheter 14 tofacilitate navigation of distal end 15 of catheter 14. In someembodiments, the flexible shaft advancement slider 28 enables theflexible shaft 12 to extend beyond the distal tip 15 of catheter 14 by adistance of greater than at least 10 mm, preferably at least 80 mm.Hypotubes 26 can extend along a telescoping hypotube seal 30 that allowsthe hypotubes 26 to telescope while maintaining a seal to help preventvacuum loss (by preventing vacuum loss in all parts of the devicebesides distal end 15 of catheter 14), thereby maximizing the vacuum andthrombectomy power at distal end 15 of catheter 14. A hypotube clamp 31secures telescoping hypotubes 26 to flexible shaft advancement slider 28for facilitation by an operator. More particularly, flexible shaftadvancement slider 28 enables the user to selectively advance flexibleshaft 12 beyond distal end 15 of catheter 14, thereby helping tofacilitate navigation in the vessels. FIG. 2 illustrates flexible shaft12 and a guidewire 50 advanced beyond distal end 15 of catheter 14 fornavigation. FIG. 3 illustrates guidewire 50 removed and flexible shaft12 locked into position within catheter 14 for thrombectomy.

In some embodiments, aspiration catheter system 10 can comprise amomentary adjustment system 29 to fine tune or adjust distal end 13 offlexible shaft 12 relative to distal end 15 of catheter 14. In otherwords, adjustment system 29, as illustrated in FIGS. 20A-23A, canprovide a variable adjustment system to adjust the relative spacing ofdistal end 13 of flexible shaft 12 to distal end 15 of catheter 14.Adjustment system 29 can be configured to permit fine tuning of therelative spacing and can be set to this relative spacing distance.However, adjustment system 29 can further be used for instantaneousand/or momentary adjustment of flexible shaft 12 relative to catheter14. In some embodiments, adjustment system 29 can comprise a rotatingscrew member 33 threadedly coupled to shaft adjustment device 25slidably disposed in housing 42. Shaft adjustment device 25 isreleasably connectable with shaft adjustment slider 28 via a latchingarm or other means. A head of screw member 33 can be captured within acavity 35 formed in a housing 42. A spring member 37 can be disposedbetween the head of screw member 33 and housing 42 to bias the head ofscrew member 33 away from housing 42 a predetermined distance, but canprovide momentary advancement of flexible shaft 12 when desired. Thatis, upon a user pressing the head of screw member 33 against the biasingforce of spring member 37, screw member 33 and shaft advancement device25, and thus coupled shaft advancement slider 28 and flexible shaft 12,can be momentarily advanced longitudinally a distance approximatelyequal to the distance the head of screw member 29 is spaced from housing42. However, rotation of screw member 33 causes threaded engagement withshaft advancement device 25 and coupled shaft advancement slider 28 toadvance or retracts advancement slider 28 and flexible shaft 12 to adesired location relative to catheter 14.

By pressing on the head of screw member 33, flexible shaft 12 can bemomentarily advance distally (in preferred embodiments, by about 1 mm-10mm) to help flexible shaft 12 better engage clot 100 that is beingaspirated by aspiration catheter system 10. In this teaching, as clot100 is pulled in, it can act to push flexible shaft 12 proximally,potentially changing the relative distance between distal tip 15 ofcatheter 14 and flexible shaft 12.

By rotating screw member 33, shaft adjustment device 25 moves proximallyor distally. Since shaft advancement slider 28 and flexible shaft 12slide locks into this part before activating thrombectomy, the relativedistance of shaft advancement slider 28 can adjust the relative distancebetween tip 13 of flexible shaft 12 and tip 15 of catheter 14. This ishelpful for any fine tuning of distance.

In some embodiments, as illustrated in FIGS. 20A-23A, an aspirationcatheter adjustment device 39 can be used to selectively adjust therelative spacing between tip 15 of catheter 14 and tip 13 of flexibleshaft 12. In this embodiment, aspiration catheter adjustment device 39comprises a lead screw 41 attached between housing 42 and adjustablecatheter sliding lock 22, which when screwed in or out cause catheter 14to move proximal or distal. Alternatively, shaft advancement slider 28can comprise a slider locking point that is adjusted using a continuousmechanism or a discrete mechanism, such a multiple snap ridges (shown),to adjust the relative distance between catheter 14 and shaft 12 when inthrombectomy mode. This can be utilized at any point during theoperation, before, after, or during thrombectomy.

With reference to FIGS. 1, 4, and 6, a drive system 32 is provided forrotatably driving flexible shaft 12 (e.g. providing rotational energy)in accordance with the principles of the present teachings. In someembodiments, drive system 32 comprises a motor 34 having an output shaft36 operably coupled to a gear set 38 operably coupled to flexible shaft12. In some embodiments, for improved packaging and efficiency, motor 34is disposed within an internal space of shaft advancement slider 28.Flexible shaft 12 and/or gear set 38 can be rotatably supported by oneor more bearings 40.

The components of aspiration catheter system 10 can be contained withina handheld, or other appropriately sized, housing 42.

In some embodiments, as illustrated in FIGS. 23-24, one or more fluidports 49 can be used to inject fluid into the lumen of a sleeve,flexible shaft 12, catheter 14, or a combination thereof. This can beuseful to deliver medication, lubricating fluid, cooling agents, andfluid to help prevent cavitation during thrombectomy and maintain stablevacuum power and remove clots.

In some embodiment, the wire is introduced into the shaft via a “Y”valve featuring a rotational hemostatic valve and an infusion port todeliver saline solution, contrast agent or other solutions into theshaft lumen as needed.

-   -   In some embodiment, the actuation of the elements of the        telescoping system can be controlled and actuated by a robotic        platform. FLEXIBLE SHAFT

With particular discussion relating to flexible shaft 12, it should beunderstood that in some embodiments flexible shaft 12 has sufficientflexibility to permit it to be bent or curved around tight corners(typically a radius of curvature smaller than 10 mm) and turn angles aslarge as 360 degrees without inducing permanent deformation for at least1″ most distal part of flexible shaft 12. In some embodiments, flexibleshaft 12 is torque resistant such that flexible shaft 12 can transmithigh rotational energy from drive system 32 to clot 100 without failure.

To this end, as illustrated in FIGS. 7A-7D, flexible shaft 12 can besolid, hollow, or a combination thereof, and/or braided or singlestranded, or a combination thereof. Hollow and/or braided configurationscan increase flexibility and torque resistance while assuring hightransmission efficiency of rotational energy. In configurationsemploying a hollow flexible shaft 12 (see FIGS. 7B-7D), guidewire 50 canextend within hollow flexible shaft 12 (see FIG. 7C) to facilitatenavigation of distal end 13 of flexible shaft 12 and/or catheter 14through the vasculature and/or can extend within a hollow portion 52 ofcatheter 14 formed in a sidewall thereof (see FIG. 7D). In someembodiments, guidewire 50 can include a defined shape at its distal end51, such as a J, U, or other shapes, if desired, to facilitateintravascular navigation. Guidewire 50 can optionally be steerable andbe advanced outside flexible shaft 12 and outside distal end 15 ofcatheter 14 to facilitate advancement of flexible shaft 12 and catheter14 into clot 100 and into the target vessel. Furthermore, flexible shaft12 can also be selectively advanced beyond distal end 15 of catheter 14and along the guidewire, creating additional scaffolding to helpfacilitate the advancement of catheter 14 to the desired position. Uponadvancement of catheter 14 in the desired position, flexible shaft 12can be withdrawn toward distal tip 15 of catheter 14 and even completelyinside catheter 14 and the guidewire 50 can be withdrawn into flexibleshaft 12 or completely outside the device as needed. Then, flexibleshaft 12 is rotated at high speed to perform thrombectomy as describedherein.

In a preferred embodiment for mechanical thrombectomy in stroke due tolarge vessel occlusion, in a particular device and operation the sameflexible shaft 12 is used as “navigation element”, “scaffolding element”and “thrombectomy element.” These functions can be reversiblytransitioned among them. This can be achieved through using a flexibleand hollow shaft 12 that can be linearly actuated by shaft advancementslider 28 and be coupled as needed with a co-axial guidewire 50, andactuated by a drive system 32 at different modalities and intensities.None of these elements need to be completely removed from the system inorder for the system to operate correctly.

The flexible shaft 12 is preferably smooth and has a tapered distal end(distal portion is preferably smaller in diameter compared to theproximal end). This flexible shaft 12, when acting as a “navigationelement”, can be atraumatically advanced over a guidewire beyond thedistal catheter opening (preferably at least 80 mm) into complex andhighly tortuous vasculature. The use of a coaxial inner guidewire 50 canimprove the ability of the shaft 12 to advance inside the catheterwithout kinking or looping which could prevent it from reaching thedistal tip of the catheter and could also damage the shaft 12. In atetra-axial system, a sleeve 45 can be added to enhance shaftadvancement. When flexible shaft 12 is acting as a “navigation element”,it can be provided with oscillating, rotational, translational, orvibrational motion, generated by the drive system 32 and/or theoperator's hand. This powered “navigation element” can aid in theplacement of guidewire 50, flexible shaft 12, and/or catheter 14 byreducing the friction between these coaxial elements and themselves andthe vasculature. This will facilitate the aspiration catheter system 10to advance through tortuous geometry, advance through irregular lumensand or stenosed geometry and facilitate advancement of a largercatheter.

The shaft 12 can serve as a “scaffolding element” by enabling thecoaxial over-the-shaft advancement of catheter 14 to challenging targetsin a manner substantially equivalent to an intermediate catheter.Although the flexible shaft 12 may be too flexible in some embodimentsto allow standalone over-the-shaft advancement of catheter 14, thecombination of the shaft 12 with an inner guidewire 50 can providesufficient structure and stiffness for over-the-shaft advancement of thecatheter 14. The advancement of the catheter 14 over the shaft 12 can befacilitated by one or a combination of oscillating, rotational,translational, or vibrational motion of the shaft 12, the catheter 14 ora combination of both, powered by the drive system 32 or the hands ofthe operator. The guidewire 50, the shaft 12 and the catheter 14 can belongitudinally translated in coupled or uncoupled fashion,simultaneously or sequentially. By way of example, some or all of thesedevices can move with respect to some or all of the other devices.

After the aspiration catheter 14 is placed in the target, generally inproximity or within the clot mass, in the preferred embodiment the shaft12 is shielded within the catheter 14, the guidewire 50 at leastpartially removed from the shaft lumen and the shaft 12 actuated by thedrive system 32 as a “thrombectomy element” to generate a hydrodynamicvortex with a steep oblique pressure gradient, as shown in FIG. 16B. Insome embodiments, as illustrated in FIGS. 8A-8B, flexible shaft 12 canbe composed of multiple segments with different diameters, windingcombinations, and/or braiding combinations. That is, flexible shaft 12can comprise a first segment 54 and a second segment 56 (or additionalsegments). This allows flexible shaft 12 to be optimized for keyparameters, such as torsional strength at the proximal end, flexibilityat the distal tip, and contraction/elongation tendency of the shaftduring navigation and high speed rotation (acts like a spring that canwind up, tightening and shortening the shaft 12, or unwind, elongatingthe shaft 12). In some embodiments the windings of shaft 12 are inopposite directions. In some embodiments, flexible shaft 12 comprises alarger diameter wind at the proximal end for torsional strength (in apreferred embodiment for a catheter with ID between 0.060″-0.070″, theshaft 12 OD is between 0.026-0.040″ with an ID of between 0.016-0.024″and a bending stiffness of approximately between 50 N mm{circumflex over( )}2 and 5000 N mm{circumflex over ( )}2, where bending stiffness isdefined as Young's modulus multiplied by the area moment of inertia ofthe flexible shaft 12) and a smaller diameter wind at and near thedistal tip (typically between 0.026-0.034″ OD with an ID of between0.016-0.024″ and a bending stiffness of approximately between 5 Nmm{circumflex over ( )}2 and 50 N mm{circumflex over ( )}2) to helpnavigate through tortuous vessels. This lower bending stiffness distallength preferably extends between 0.5″-20″ from the distal tip 13 offlexible shaft 12. It should be appreciated, as illustrated in FIG. 8C,that multiple shaft 12 segment configuration can be achieved by varyingthe cross-sectional size of the wire used to construct flexible shaft 12from a diameter dp to a diameter dd, where diameter dp is larger,smaller, or different than diameter dd. Moreover, multiple layers ofwindings can be added to achieve various torsional and bending stiffness(see FIG. 8D). Furthermore, different materials can be used to achievedifferent shaft stiffness. These materials are commonly stainless steelor nitinol. Centerless grinding can also be used to reduce the outerdiameter of flexible shaft 12 in certain sections to reduce thestiffness of that shaft segment. The shaft 12 can be a combination ofcoiled or braided metal such a nitinol or stainless steel and aplasticto form a plastic/metal composite. Lined braided shaftconstructed with inner liner, braid, and the outer jacket can be used toprovide required lubricity, torque transmission, fatigue resistance,pushability, steerability, and deformation and kink resistance. In thisdesign, jackets of different polymers and thicknesses can be added tooptimize torsional strength and bending stiffness. This can provide goodtorque transmission for rotational motion and also reduce frictionbetween different elements in the telescoping system. The braiding/coilscan also be raised up from the surface of the shaft to minimize thecontact surface between the shaft and catheter(s) surrounding it. Shaft12 can also be comprised of longitudinal fibers and fibers included inthe coiling or braiding, for example of Kevlar, to prevent shaftelongation or separation in the event of shaft fracture. Polymer jacketand liners can also be included in the shaft 12 to prevent shaftseparation in the event of wire fracture.

The outer diameter of flexible shaft 12 is preferably 20-80% of theinner diameter of aspiration catheter 14. Larger shafts 12 toleratehigher torque and bending force during thrombectomy and facilitateatraumatic coaxial advancement of the catheter 14. However, largershafts 12 tend to cause drop in vacuum power and flow and may notadvance easily over a guidewire 50 into the intravascular space duringnavigation. Smaller shaft 12 may navigate easier and minimize vacuumpower loss although may not provide enough structure for coaxialadvancement of catheter 14 or resist the torque load needed for vorticesgeneration. Furthermore, higher torque and strength can be obtained byincreasing the pick count and using larger diameter braid wire, althoughthese will translate into higher stiffness and decrease flexibility.

In some embodiments, the same shaft 12 can have different zones tooptimize torque resistance and rotational energy by a combination offeatures described herein. These zones can be created by welding,gluing, grinding, braiding, including jackets and liners, or othermethods known to those skilled in the art. The changes in shaft designcan be a continuous transition, a step-wise transition, or a combinationof both. For example, at the base of flexible shaft 12 closest to thedrive system 32, the winding of flexible shaft 12 can be very tight andpotentially include a larger diameter wire and/or stronger jacket tohelp resist to the high torsional forces that are typically experiencedat that location. Then, toward the distal end of flexible shaft 12, thewinding of flexible shaft 12 and/or diameter of flexible shaft 12 and/orthe jacket can be progressively diminished as smaller torsional forcesare typically experienced near the distal end. This can act to enhancethe flexibility and/or diminish flexible shaft 12 diameter whileoptimizing delivery of rotational energy to enable thrombectomy. In someembodiments, the jacket can be very thin or absent at least partially inthe distal end of the flexible shaft 12 to uncover braid or coil textureto generate hydraulic features and interact with clot 100.

In some embodiments, flexible shaft 12 can be a continuous structure orcan be formed by multiple segments. These segments can be connected toone another using, for example but not limited to, adhesives, welding,liners, or other joints that allow transmission of rotational forces.

The coiling density (coils/length/number and thickness of filars) offlexible shaft 12 can be different within different flexible shafts oralong the length of the same shaft. In one embodiment there are between3 and 12 filars with a thickness between 0.003-0.008″. Typically, alarger filar count and larger filar thickness correspond to a stifferand stronger shaft whereas a smaller filar count and a smaller filarthickness correspond to a more flexible and compliant shaft with lowerbending stiffness. Additionally, a shaft with a larger outer diameterwill typically have higher stiffness and torsional strength whencompared to a shaft with a smaller outer diameter.

Higher torque and strength can be obtained by increasing the pick countand using larger diameter braid wire of the shaft 12, although thesewill translate into higher stiffness and decrease flexibility. In someembodiments, the wire size is 0.001-0.006″ with a pick per inch of 20 to600.

The cross-sectional design of flexible shaft 12 can be of a variety ofdifferent geometrical shapes, with examples of shapes including but notlimited to circular, triangular, square and others. The cross-sectionaldesign of flexible shafts can be different within different shafts oralong the length of the same shaft. Therefore, it should be recognizedthat flexible shaft 12 (and catheter 14) do not need to have constantdiameter along the total length of the device. In some instances, it canbe beneficial to increase shaft and catheter diameter in the proximalend where high strength and pushability, or the ability for an object tobe pushed/advanced without kinking or looping, but less flexibility isrequired. In one embodiment the outer diameter of the proximal end offlexible shaft 12 is approximately 0.036″ with approximately 8 filarwindings while the distal end is approximately 0.032″ with 4 filarwindings. In other instances, it can be beneficial to increase thediameter of catheter 14 toward the distal end to enhance vacuumefficiency and thrombectomy efficacy.

In some embodiments, the flexibility and torque resistance of flexibleshaft 12 can be modified by changing diameter, material, geometric,jacket and braiding features of flexible shaft 12 and/or by introducinga guidewire 50 with different stiffness within flexible shaft 12.

In some embodiments, flexible shaft 12 is made of one or more metals,such as stainless steel and/or nitinol. It can be made through windingand/or braiding filament around a mandrel to produce a hollow shaft. Theshaft 12 preferably includes a hollow channel to enable a guidewire 50to be coaxially advanced within the flexible shaft 12 for systemnavigation, while simultaneously achieving sufficient torsional strengthto resist breaking during use. In some embodiments, a polymer liner isincluded to provide a high degree of lubricity on the inner channel tofacilitates the passage of a guidewire 50 or other devices through thelumen.

In some embodiments, flexible shaft 12 can be composed of multiplelumens that are either connected, un-connected, or a combination thereofto one another. As an example, there can be three shafts, each withtheir own lumen, that are combined to form an additional lumen where aguidewire can be slid through.

In some embodiments, the shaft 12 can be disposed and advanced into thevasculature without an internal guidewire 50. This shaft 12 can besteerable and, in some embodiments, can have a pre-formed shaped.

In some embodiments, the shaft 12 can acquire a shape after removal ofthe inner guidewire 50 or by unsheathing from a surrounding sleeve 45,or can be linear and acquire a shape after introduction of the guidewire50. In some embodiments, as illustrated in FIGS. 8A-8B and 9A-9F,flexible shaft 12 comprises one or more hydraulic inducing features 58that enhance hydraulic forces during rotation of flexible shaft 12.Hydraulic enhancing features 58 can include, but are not limited to,fins, bumps, ridges, and surface micro features, either along the entireshaft of flexible shaft 12, near distal end 13 of flexible shaft 12, orattached to distal end 13 of flexible shaft 12. In some embodiments,hydraulic enhancing features 58 increase hydraulic force to enhancedestruction and/or maceration of clot 100.

In some embodiments, as illustrated in FIGS. 8A-8B, 9A-9F, and 10A-10D,flexible shaft 12 comprises one or more eccentric features 60 to furtherinduce translational motion of flexible shaft 12 to enhance thethrombectomy mechanism. It should be understood that in some embodimentshydraulic enhancing features 58 and eccentric features 60 may be thesame feature performing both functions. These eccentric features 60 canbe in the form of an eccentrically wound shaft, an eccentric mass fixedto part of flexible shaft 12, an eccentric tip on flexible shaft 12, ora combination thereof. An ideal eccentric feature 60 will be minimal insize so as to not significantly decrease the flexibility of flexibleshaft 12 while still being large enough to induce translational motionin flexible shaft 12 during rotation. In addition, it should ideally betapered and have an atraumatic configuration to enable safeintravascular navigation of the shaft, unless a sleeve 45 is used toshield cutting and/or abrasive surfaces. This eccentric feature can beof any length and disposed at any point or several points along thelength of flexible shaft 12, and may even extend beyond the distal mostend of flexible shaft 12. The eccentric feature could be made of aradiopaque material such as tantalum or Platinum Iridium. The eccentricmass can be single or multiple. In a typical device for removing clotsin large cerebral artery, the eccentric mass can have a thickness of0.001 to 0.020 inches, a length of 0.1 mm to 5 millimeters, and consistof a full ring or partial ring. The eccentric mass can be completelyembedded within the jacket and outer liner of the shaft leading toatraumatic shape and surface for navigation with functional eccentricityfor thrombectomy.

Eccentric features 60 can as well have cutting geometries andthrombectomy enhancement features, although not all thrombectomyenhancing features are necessarily eccentric components.

In another embodiment, an off-center channel at least partially alongthe shaft 12 or the shaft tip 64 can create eccentric features.

Flexible shaft 12 can also have features including but not limited to anabrasive coating, surface micro features and patterning to augmentfriction between flexible shaft, the fluid environment 12 and clot 100.This can translate into stronger hydrodynamic waves and grasp of clot100 by flexible shaft 12 resulting in enhanced corkscrew inward tractionof clot 100 into catheter 14.

Flexible shaft 12 can also have features including but not limited to alubricious coating in the outer and/or inner lumens at least partiallyalong its length to reduce friction between the shaft 12, the guidewire50 and the catheter 14.

Flexible shaft 12 can be advanced or withdrawn to optimize its positioninto the maximal thrombectomy zone 74 to optimize the interactionbetween shaft and clot 100 in the engagement zone. In addition, it canbe completely withdrawn from catheter 14 and exchanged if needed.

The advancement or retraction of flexible shaft 12, guidewire 50, and/orcatheter 14 can be enhanced by very low speed rotation (typically <200rpm), vibration or oscillation (typically greater than 2 Hz) of flexibleshaft 12 by the user's hand or a drive system 32. It should be notedthat this operation mode is for device navigation. For thrombectomy, thepreferred embodiment is with flexible shaft 12 fully contained withincatheter 14 and rotated at higher speeds as set forth herein.

In some embodiments, flexible shaft 12 can be navigated into thevasculature as described herein, and then used as scaffolding to advancea catheter over-a-shaft. The advancement or retraction of catheter 14can be enhanced by very low speed rotation (typically <200 rpm),vibration, or oscillation (typically greater than 2 Hz) of catheter 14by the user hand or a motor (same or different motor than motor causinghigh speed rotation for vortex generation). The same shaft can havedifferent zones to optimize scaffolding by a combination of featuresmentioned above.

In some embodiments, as illustrated in FIGS. 8A-8B and 11A-11F, flexibleshaft 12 comprises a shaft tip 64 that is connectable, coupled, orotherwise extending from distal end 13 of flexible shaft 12. In someembodiments, shaft tip 64 can be rounded and have smooth atraumaticedges 66 during navigation in the vessel, and have one or more sharpedges 68 during thrombectomy mode. This can be achieved by, but notexclusively by: 1) including grooves in an angled position, resulting intwo edges, one sharp and the other dull (see FIGS. 11A-11C). Whenflexible shaft 12 rotates clockwise, the sharp edge moves forward toengage and cut clot 100 (active thrombectomy mode). When flexible shaft12 rotates counter-clockwise (navigation mode) the sharp edge moves awayfrom the surrounding tissue facilitating shaft advancement into thevascular lumen by low-speed rotation. Shaft tip 64 can be otherwiserounded or smooth to facilitate advancement with the introduction of theguidewire 50 for navigation mode. In some embodiments, shaft tip 64includes a lumen in the tip that is co-axially oriented to the mainlongitudinal axis of flexible shaft 12 with a taper that varies insteepness through the circumference of the tip gradient, resulting in asmooth and rounded tip with the introduction of the guidewire 50 fornavigation mode, and a “spoon” notch in flexible shaft 12 tip for clot100 maceration upon wire removal. It should be noted that the latter twoembodiments, or any variations of such embodiments, create an off-centermass that will enhance orbital movement of flexible shaft 12 and vortexgeneration upon rotation at high speed. As the outer diameter ofguidewire 50 is smaller than shaft inner diameter, the off-center masscan be enhanced by shifting the lumen of the tip away from thelongitudinal axis of flexible shaft 12. In some embodiments,thrombectomy enhancement features can be cutting geometries, surfacefeatures, and deployable element of shaft 12. By advancing orwithdrawing sleeve 45 over the shaft during navigation or thrombectomymodes: 1) cutting geometries and surface features can be shielded orexposed; 2) deployable elements can be folded or unfolded; 3) pre-shapedconfigurations can be rectified or released. The latter configurationcan be as well achieved by removing the guidewire 50. In someembodiment, the thrombectomy enhancement features can be reduced byintroduction of guidewire 50.

In one embodiment, cutting geometries may have a given rake angle (α),inclination angle (λ), cutting speed (v), as illustrated by point A (seeFIGS. 26A-26D). A is defined by a radius r and an offset (e). Theinclination angle at point A is

${{\lambda (r)} = {\sin^{- 1}\frac{R_{o} - e}{r}}},{R_{I} \leq r \leq R_{O}},$

where Ro is the OD of the cutting tool. In practice, high λ enables moreeffective cutting of compliant tissue, including thrombus material. Insome embodiments, introduction of guidewire 50 diminishes the cuttinggeometry and results in a smooth and rounded shaft tip 13 for navigationmode.

In some embodiments, the surface may have features, such asmicro-dimples, micro-indentations, micro-grooves or the combination.Those features create unsteady micro-scale vortices and increase theturbulence intensity near the shaft. This creates local large pressurefluctuation and generates impact on the thrombus material that may leadto micro-damages to the thrombus material. Those features also increasethe ability of the shaft dragging the thrombus material.

In some embodiments, deployable elements 59 may be added to facilitateremoving of thrombus material (see FIGS. 27A-28B). Before deployed, thedeployable element has minimum cutting power. Once deployed, theelement's outer diameter increases, and the removing mechanism isenhanced. The deployable element can have the above-mentioned cuttinggeometries and surface features and the combination of them. In someembodiments, the deployable element can be made of shape-memory alloysuch as nitinol. The deployable element will deploy and or expand andrecover its original shape upon unsheathing of the shaft. In someembodiment, as illustrated in FIGS. 27A-28B, during thrombectomy thehydraulic enhancing features 58 can be deployed by high speed rotationof the flexible shaft 12 and interaction with the clot mass 100 andfluid (see FIGS. 28A-28B), and fold back in an undeployed restingposition (FIGS. 27A-27B) upon sufficient decrease in the rotationalspeed for low-profile navigation. In some embodiment, the deployableelement can be made of radiopaque material and function as well asfluoroscopic marker.

In some embodiments, the shaft 12 can be shorter than the telescopingsystem and disposed within the aspiration catheter 14 in a distallocation. The shaft 12 can be moved longitudinally in a coupled oruncoupled fashion from the aspiration catheter 14. The movement of theshaft 12 can be achieved by mechanical coupling of the shaft to one ormore wires controlled by the actuator module or the operators hand. Thewire or wires are connected distally at least partially into theproximal end of the shaft and are disposed inside, outside or within thewalls of the aspiration catheter 14 or a combination of it. The wire orwires are connected proximally to a slider within an actuator ordirectly operated by the operator's hands. The wire can be advancedtowards the catheter, which causes the shaft to emerge from the catheterand advance into the vascular lumen as a navigation element (this can besupported by the use of a co-axial guidewire if needed inside theshaft). In this position, the shaft 12 provides scaffolding for catheteradvancement to target during navigation mode. The length of shaft 12deployment varies depending on the vascular anatomy that has to benavigated but typically is between 1cm and 30cm. After advancing thecatheter 14 to target, the shaft 12 can be retracted into the catheterlumen 14 by withdrawing the wire and can be actuated to generatevortices forces for thrombectomy. The actuation of the shaft 12 can bedriven by mechanically transmitting the rotation of one or more wires tothe shaft through a system of gears and belts or alike. In thisembodiment, the wire is coupled to a motor capable of generating enoughrotational speed to generate vortices forces by transmitting enoughrotational energy to the shaft 12. In another embodiment, the shaft 12rotation can be generated by delivering pressurized solutions to theshaft featuring blades or fins or grooves. The wire adjusting theposition of the shaft can be a solid or hollow, monofilament, coil orbraid or any combination thereof. The telescope system in thisembodiment can improve vacuum efficiency and flow by reducing the extendof shaft 12 disposed within the suction catheter 14, and optimizestorque transmission while reducing wear and tear by disposing a wire inthe segments of the telescope system traversing tortuous anatomy andenabling vortices generating forces by the shaft in the regions of thecatheter of maximal need for thrombectomy, typically the most distal 5cm.

Catheter

In some embodiments, catheter 14 is configured to be navigated throughvascular geometries, and is made from pliable material. In someembodiments, catheter 14 is made sufficiently stiff to not collapseunder suction force or kink upon small bending radius. In someembodiments, catheter 14 is structurally reinforced to prevent kinkingof the lumen with bending. In a typical embodiment, a polymer linedbraided catheter with inner liner, braid, and outer jacket is used toachieve lubricity, torque, pushability, steerability, and kinkresistance. For treatment of stroke due to large vessel occlusion, innerdiameter of catheter range 4-6 French, although smaller and larger sizescan be used depending on the application.

In some embodiments, wall surface 17 of catheter 14 has a hollow channelthat spans the length of catheter 14 and opens distally. This hollowchannel enables a guidewire 50 to be disposed within the wall ofcatheter 14 (FIG. 7D). This guidewire 50 can optionally be steerable andbe advanced outside the distal end of catheter 14 into the vascularlumen to facilitate and direct advancement of catheter 14 into the massof clot 100 and into the target vessel, both before, during, or aftermechanical thrombectomy by powering flexible shaft 12 in catheter 14 asdescribed herein.

In some embodiments, as illustrated in FIG. 12, the combination offlexible shaft 12 and catheter 14 can define one or more zones that areparticularly adapted and configured to perform mechanical thrombectomyupon clot 100. As disclosed herein, flexible shaft 12 is positionedwithin catheter 14 and is rotating at a very high speed to createhydrodynamic vortices and corkscrew movements to further disrupt clot100. Generally, a clot engager zone 70 is located from distal end 15 ofcatheter 14 and proximally extends within catheter 14 to a location 72proximal from distal end 13 of flexible shaft 12. A maximal thrombectomyzone 74 is further proximally located relative to clot engager zone 70,although maximal thrombectomy zone 74 can overlap clot engager zone 70to some, all or no extent. Maximal thrombectomy zone 74 can be bound ata distal end 76 (extending distally past distal end 13 of flexible shaft12) and a proximal end 78 (extending proximally relative to distal end13 of flexible shaft 12). An anti-clog zone 80 is still furtherproximally located relative to maximal thrombectomy zone 74 andgenerally extends within catheter 14.

In some embodiments, the distal most segment (e.g. clot engager zone 70)of catheter 14 may be at an angle to the longitudinal axis of catheter14.

Clot engager zone 70 anchors clot 100 to catheter 14 optimizing thethrombectomy mechanisms described herein. In addition, clot engager zone70 maintains clot 100 anchored to catheter 14, minimizing release offree fragments. The combination of shaft orbital translation, shafttransverse vibration, and torsional indraft pull following a corkscrewpathway due to pressure gradient, flow shear, and contacting forcebetween flexible shaft 12 and contacting clot 100, and vacuumoverlapping at clot engager zone 70 provides a synergetic thrombectomymilieu that is safely contained within catheter 14. In addition, clotengager zone 70 provides a safety buffer zone to allow the periodicelongation and contraction of flexible shaft 12 when it is rotated athigh speed, such that flexible shaft 12 is not disposed on the outsideof catheter 14 where it can potentially cause damage to the bloodvessels or body cavity.

In some embodiments, at least the maximal thrombectomy zone 74 ofcatheter 14 will have a reinforced segment 82 to increase the structuralresistance of catheter 14 to forces and energy transmitted by the motionof flexible shaft 12, as shown in FIG. 12. This segment 82 can be coatedwith anti-abrasive material, have reinforcing coils and/or bands. Insome embodiments, distal end 15 of catheter 14 and maximal thrombectomyzone 74 can be structurally reinforced to prevent collapse of the lumenof catheter 14 with vacuum.

In some embodiments, at least the maximal thrombectomy zone 74 ofcatheter 14 and flexible shaft 12 comprise fluoroscopic markers to aidin the positioning of distal end 13 of flexible shaft 12 and/or thecatheter 14 in optimal position for activation. In some embodiments,these fluoroscopic markers can be designed to align the thrombectomycomponents to indicate a range of acceptable tolerances in shaftpositioning. In some embodiments, the fluoroscopic marker of a catheter14 can be ring shaped and disposed in the region of maximalthrombectomy. In this embodiment, the fluoroscopic marker of the shaftcan be an incomplete ring but longer than that catheter marker. In thisembodiment, the appropriate alignment of both fluoroscopic markers wouldcreate a “T” detectable by fluoroscopy. In other embodiments, thefluoroscopic marker of the shaft is complete but smaller than thecatheter marker, leading to fluoroscopic double ring sign when thecatheter and shafts are appropriately aligned. n some embodiments,fluoroscopic markers, CT and MRI markers can be provided in any portionof catheter 14, guidewire 50, sleeve 45, and/or flexible shaft 12.

In some embodiments, distal end 15 of catheter 14 includes one or moreuneven features 84 disposed thereon (e.g. rounded bumps). In someembodiments, features 84 can be along the same direction as the longaxis of catheter 14. Features 84 help to penetrate and break apart clot100 due to concentrated areas of high shearing force as clot 100 isdragged inward into maximal thrombectomy zone 74 following a corkscrewpath.

In some embodiments, catheter 14 can have one or multiple inner andouter diameters and have multi-durometer construction.

In some embodiments, catheter 14 can have windows in the wall tofacilitate clot removal.

In some embodiments, the catheter distal end 15 can be beveled toimprove the contact of the clot to the catheter the shaft.

In some embodiments, as illustrated in FIGS. 8B and 13A-13C, catheter 14may have accessory lumen, channel, or holes 86 in the wall to allowfluid (saline solution, blood, medication, etc.) to fill the lumen ofcatheter 14 preventing cavitation upon vacuum and maintain theenvironment needed to generate hydrodynamic forces, and aid in removalof material. Moreover, in some embodiments, as illustrated in FIGS. 7D,8B, and 13A-13C, catheter 14 may have accessory lumen or channel 88throughout the totality or part of its extension to allow guidewire 50or other wire to be disposed within for navigation or to infusesolutions or medications. Particularly, as illustrated in FIG. 13A, achannel 88 can be disposed within the sidewall of catheter 14 to delivera fluid. As illustrated in FIG. 13C, channel 88 can extend along anancillary channel of catheter 14. In some embodiments, the fluid can bedelivered through the hollow interior of flexible shaft 12 (FIG. 13B).

In some embodiments, wall surface 17 of catheter 14 has a hollow channelthat spans at least part of the length of catheter 14 and opens at thedistal end of catheter 14, into the lumen of catheter 14, or acombination thereof. This hollow channel enables the advancement of aguidewire 50 to be used in monorail system, both during navigation modeof catheter 14 (with or without co-axial advancement over a shaft) andthrombectomy mode. In the latter option, flexible shaft 12 is rotatingat very high speed inside catheter 14 causing clot 100 engagement andfragmentation while catheter 14 is advanced or pulled back over themonorail wire disposed in the vascular lumen, and not in contact withflexible shaft 12 (FIG. 8).

In some embodiments, wall surface 17 of catheter 14 has a hollow channelthat spans at least part of the length of catheter 14 and opens at thedistal end of catheter 14, into the lumen of catheter 14, or acombination thereof. This hollow channel enables the advancement of adistal embolization protection device, such as a net or filter, that canbe advanced through clot 100 mass and: 1) be pulled back facilitatingentrance of clot 100 into catheter 14; 2) remain distal to clot 100 tocapture embolization particles and then be pulled back allowing theseparticles to be removed by catheter 14.

In some embodiments, wall surface 17 of catheter 14 has a hollow channelthat spans at least part of the length of catheter 14 and opens at thedistal end of catheter 14, into the lumen of catheter 14, or acombination thereof. This hollow channel enables the advancement of anocclusive device, such as a balloon, which can be advanced through clot100 mass and then: 1) insufflated to prevent distal embolization bystopping anterograde flow, 2) be pulled back facilitating entrance ofclot 100 into catheter 14.

In some embodiments, wall surface 17 of catheter 14 or flexible shaft 12can have a hollow channel to deliver medication, cooling fluids or otheragents toward the distal end of catheter 14.

In some embodiments, catheter 14 may have a flow occlusion mechanism,such as one or more balloons, near or at the distal end 15 to enhancesuction force applied to the region of interest, reduce the pressureupon which the material needs to be removed, and diminish or stop flowminimizing distal embolism.

In some embodiments, catheter 14 includes a filter device for capturingundesirable material and removing it from the fluid flow.

Thrombectomy Forces

The rotation of flexible shaft 12 contained within catheter 14 induceskey engagement and fragmentation mechanisms (see FIGS. 14A-14B, 15A-15D,16A-16B, 19A-19G), such as, but not limited to:

-   -   a. Hydraulic forces created between flexible shaft 12 and the        inner wall surface 17 of catheter 14 due to the rotation of        flexible shaft 12 within catheter 14 and the induced uncoupled        translational motion of flexible shaft 12 (see FIGS. 14A-14B)        that fragments clot 100 within catheter 14.    -   b. The hydraulic forces created by high speed shaft rotation and        orbiting coupled with vacuum generate a vortex with a steep        pressure gradient obliquely oriented in the lumen of catheter 14        and rotating inside catheter 14 (see FIGS. 16A-16B).    -   c. This vortex generates a torsional indraft pull following an        inward corkscrew pathway to further engage clot 100 into        catheter 14 and create shear stress that is more effective than        stand-alone vacuum to anchor, pull, and fragment clot 100 (see        FIGS. 19A-19G).    -   d. The vortex also potentiates clot 100 engagement,        fragmentation, and inward movement of the clot 100 proximally        within catheter 14 due to the transformation of static friction        between clot 100 and inner wall 17 to kinetic friction which        tends to produce a lower resistive force between clot 100 and        inner wall 17.    -   e. The high frequency excitation of flexible shaft 12 fragments        clot 100 further and causes flexible shaft 12 to repeatedly hit        the inner surface of catheter 14 (see FIGS. 15A-15D)). This        creates a high frequency (typically 100 to 300 Hz), low        amplitude vibration (typically 50 μm to 200 μm) of catheter 14        that aids in clot 100 disruption, indicated as the “vibration”        in FIG. 14A.    -   f. The high-speed rotation of flexible shaft 12 in combination        with the coiled or braided wire design of flexible shaft 12        induces a periodic elongation and contraction of flexible shaft        12 due to torsional vibration and unstable turbulent flow,        indicated as the “elongating and contracting” in FIG. 14B. This        dynamic forward and backward movement of a distal end 13 of        flexible shaft 12 lengthens the zone 74 of maximal thrombectomy        efficacy. By way of non-limiting example, periodic elongation        and contraction can be within about 0.1 to 5 mm, based on shaft        material, winding pattern, wire diameter, torsional modulus,        vessel tortuosity, and the like.    -   g. The hydrodynamic forces generated by high speed rotation of        flexible shaft 12 induces 3-dimensional corkscrew movement of        flexible shaft 12, which swipes between inner wall surface 17 of        catheter 14 and clot 100 surface. This minimizes static friction        between clot 100 and wall surface 17 of catheter 14,        de-attaching clot 100 from wall surface 17 of catheter 14, and        enhancing clot 100 removal by transforming static friction to        kinematic friction. It should be understood that the        three-dimensional corkscrew configuration and movement of        flexible shaft 12 is achieved upon application of high-speed        rotational motion (typically greater than 10,000 RPM).    -   h. At rest, the flexible shaft 12 substantially defines a        straight, linear profile, without the need for complex preformed        shapes, such as angles, J's, sinusoids, and the like. In some        embodiments, non-linear shapes of flexible shaft 12 at rest can        be used in connection with the present teachings. These shapes        can be fixed or acquired after removal of inner guidewire 50.    -   i. Static friction is substantially reduced or eliminated by the        steep pressure gradient obliquely oriented in catheter 14 that        rotates inside catheter 14 and extends throughout the lumen of        catheter 14.    -   j. The movement of flexible shaft 12 also engages with clot 100        substance enhancing/accelerating the inward corkscrew path to        further engage and fragment clot 100.    -   k. The same mechanisms described herein can occur from the        distal end of the maximal thrombectomy zone 74 to the proximal        end of catheter 14 with decreased intensity preventing the lumen        from clogging, indicated as the anti-clog zone 80 in FIG. 12A.    -   l. Features on flexible shaft 12, such as but not limited to        thrombectomy enhancing features and angled eccentric mass 58, 60        on distal end 13, can further act to pull clot 100 into catheter        14 by transmitting axial and tangential forces to clot 100.

In some embodiments, to enhance the axial force of the rotating shaft12, magnets can be added the catheter 14 and flexible shaft 12 such thatwhen flexible shaft 12 is rotated with respect to catheter 14, the polesof the opposing magnets periodically attract and repel one another. Insome embodiments, one or more magnets can be included in any of theelements of the telescoping system to prevent the release of freemagnetic fragments. In some embodiments, the system may include areinfusion cannula to reintroduce the fluid removed from the patientback into the patient.

In some embodiments, to enhance the hydrodynamic force on the rotatingshaft 12, hydrophilic coatings can be applied to shaft 12.

Sleeve

In some embodiments, a tri-axial telescoping system will be enhanced bythe addition of a sleeve 45 to be disposed between flexible shaft 12 andcatheter 14. This tetra-axial system may enhance both navigation andthrombectomy as described below.

In some embodiments, sleeve 45 is made from pliable material butsufficiently stiff to not collapse or kink upon small bending radius andentrap the inner flexible shaft 12. Sleeve 45 can be moved along thelongitudinal axis of catheter 14 by a sleeve advancement slider 47 in acoupled or uncoupled fashion with shaft advancement slider 28. Sleeve 45can have the following functions depending on the embodiment andconfiguration as detailed below.

In one embodiment, sleeve 45 can be selectively advanced beyond distalend of catheter and at least partially over flexible shaft 12, creatingadditional scaffolding to help facilitate the advancement of catheter tothe desired position and decreasing the shelf between flexible shaft 12and catheter. In this embodiment, sleeve advancement slider 47 can becoupled to shaft advancement slider 28 to enable synchronous movementsof these two structures co-axially, and can be uncoupled anytime to moveindependently flexible shaft 12 or sleeve 45. Upon advancement ofcatheter 14 in the desired position, the guidewire 50 can be withdrawninto flexible shaft 12, flexible shaft 12 can be withdrawn insidecatheter 14 and sleeve 45 can be withdrawn into catheter 14 exposing atleast a part of flexible shaft 12 to enable the generation ofthrombectomy forces upon high speed rotation.

In some embodiments, as illustrated in FIGS. 25A-25B, sleeve 45 can beselectively advanced distally relative to flexible shaft 12 therebyshielding the thrombectomy enhancement features. This is convenientduring the disposal or insertion of distal end 13 of flexible shaft 12into the vascular bed during navigation mode as flexible, tapered,smooth and featureless configurations will minimize endovascular damage.In this embodiment, during navigation mode the sleeve 45 can beselectively advanced at least partially over flexible shaft 12 byuncoupled advancement of the sleeve slider 47 over a temporarily fixedshaft advancement slider 28. Upon advancement of catheter 14 in thedesired position, the guidewire 50 can be withdrawn into flexible shaft12, flexible shaft 12 can be withdrawn inside catheter 14 and sleeve 45can be withdrawn further into catheter 14 exposing at least a part ofthe distal flexible shaft 12.

In some embodiments, the distal segment of sleeve 45 can be elastic tocinching over a guidewire when selectively advanced distally to the endof flexible shaft 12. This will shield any thrombectomy enhancingfeatures of flexible shaft 12 and will create a more taperedconfiguration for enhanced navigation.

In some embodiments, during thrombectomy mode, sleeve 45 can beretracted to unsheathe thrombectomy enhancing features 60 of flexibleshaft 12, unleashing the highly flexible shaft 12 to generatethrombectomy forces upon high speed rotation, and increase the availablecross-sectional lumen to facilitate clot engaging and removal withmaximal vacuum power.

In some embodiment, sleeve 45 can be selectively advanced along flexibleshaft 12 to unload flexible shaft 12 of any clot debris. In anotherembodiment, flexible shaft 12 can be selectively withdrawn further intosleeve 45 to remove the clot debris coating flexible shaft 12. Thesefunctions can be accomplished by uncoupled co-axial motion of sleeve 45over flexible shaft 12 concurrent or not to rotation of these elementsalong their main axis. Uncoupled motion can be optionally done, forexample, with discrete notches or a continuous distance adjustmentmechanism, with or without a spring system.

In some embodiments, sleeve 45, catheter 14, and/or flexible shaft 12can have features to enhance clot debris stripping from flexible shaft12, such as cutting edges or ridges, tight tolerance, elastic recoil,reinforcement bands, and chip breakers.

In other embodiment, sleeve 45 can be used as a channel to actively orpassively infuse solutions from fluid port 49 (for example, medications,physiological fluids, lubricious solutions, cooling solutions) oraspirate before, during, or after the thrombectomy.

Method

With reference to FIGS. 17A-17G, in some embodiments during clotmaceration and removal, guidewire 50 is advanced within the lumen of thevessel/cavity/space to clot 100 (FIG. 17A). Distal end 13 of flexibleshaft 12 is then advanced along guidewire 50 and placed in proximity,within or passed the mass of clot 100 (FIG. 17B). The longitudinaldisplacement of the shaft 12 can be facilitated by low speed rotation,oscillation, or vibration by the dive system 32. Distal end 15 ofcatheter 14 is then navigated into the target vessel/cavity/space andplaced in proximity, within, or past the mass of clot 100 (FIG. 17C).During this navigation and positioning, it can also be advantageous toretract shaft 12 in cooperation with the advancement of catheter 14.This can be achieved through manual or automatic retraction actuation ofshaft advancement slider 28 in cooperation with manual or automaticadvancement of catheter 14 by means of vacuum port assembly 18 and/oraspiration catheter system 10. In some embodiments, catheter 14 can befurther supported internally and/or externally using additionalsupporting elements such as a guiding catheter, an introducer, sleeve45, or combinations thereof. Guidewire 50 can be retracted or fullyremoved from the vessel or aspiration catheter system 10. Flexible shaft12 is positioned in catheter 14 to reach maximal thrombectomy zone 74(FIG. 17D). Suction from vacuum source 24 begins and draws clot 100portion into clot engager zone 70 of catheter 14 either prior,concurrent and/or after the flexible shaft 12 is rotated at high speedin accordance with the principles of the present teachings. Thrombectomyis fully contained within catheter 14 as described herein. Catheter 14and clot 100 remain engaged during the thrombectomy stage (FIGS. 17E-17Gand 19A-19G). Suction continues and clot 100 enters further into maximalthrombectomy zone 74 of catheter 14. Flexible shaft 12 is furtherrotated inside catheter 14 at high speed generating thrombectomy by themechanisms described herein. However, as needed during the thrombectomyprocedure, the rotation of flexible shaft 12 can be momentarily stoppedand once again become the navigation and scaffolding element if needed.The fragmented clot 100 inside catheter 14 is continuously aspiratedaway from the vascular lumen and undergoes further fragmentation alongthe total length of catheter 14 by the mechanisms described herein.

In some embodiments, the relative distance between flexible shaft 12 andcatheter 14 can be adjusted by the shaft adjustment device 25 and/or themomentary adjustment system 29, and/or catheter adjustment device 39before, during, or after the thrombectomy under X-ray guidance.

In some embodiments, fragmentation and/or maceration of clot 100 areonly active in maximal thrombectomy zone 74 (FIGS. 17E-17G).Simultaneously, un-fragmented clot 100 is dragged inwards into clotengager zone 70 and then further into maximal thrombectomy zone 74 forfurther thrombectomy as described herein.

In some embodiments, the action of thrombectomy and maceration in FIGS.17E-17G results in catheter 14 advancing into the substance of clot 100and distally into the target vessels until complete removal of clot 100is achieved (FIG. 17G).

In some embodiments, catheter 14 can be navigated within or passing theclot mass and then receded during thrombectomy until complete removal ofclot 100 is achieved.

In some embodiments, sleeve 45 can be advanced at least partially overflexible shaft 12 to facilitate advancement of catheter 14 to target,and then at least partially withdrawn to enable the generation ofthrombectomy forces between flexible shaft 12 and catheter 14.

In some embodiments, as illustrated in FIGS. 18A-18D, a secondary wire99 can be used to guide catheter 14 and flexible shaft 12 duringthrombectomy. The secondary wire 99 can be located in channel 52 ofcatheter 14 or along a channel thereof.

In some embodiments, flexible shaft 12 can be actuated at or near theproximal end of flexible shaft 12 to induce translational motion atleast at the distal end of catheter 14. This can be used bothexclusively and in conjunction with the rotational motion to increasethrombectomy capability.

In some embodiments, shaft 12 can be rotated at high speed outside (e.g.beyond) distal end 15 of catheter 14 following orbital movements thatextend along a path that can be larger than the diameter of catheter 14.The diameter of this orbital movement of shaft 12 outside catheter 14 isdependent upon the rotational speed, the length of shaft 12 protrudingoutside catheter 14, the ID of catheter 14, and the flexibility of shaft12. The translational movement of a shaft 12 with enough stiffness toact as cutting tool will generate a cutting cone to fragment tissues andclots 100. This can be coupled with vacuum to removed fragmented debris.This can be coupled by a bipolar mechanism (between an electrified shaftor shaft tip and catheter 14 distal-most opening) to induce bipolarcurrent and simultaneous coagulation during tissue maceration. This canalso be coupled to hollow channel 52 along the wall of catheter 14 thatenables a fluid media to be delivered at or near the distal end ofcatheter 14 which can then backfill the lumen of catheter 14 via vacuum.This would enable the generation of hydraulic forces and translationalshaft motions when catheter 14 is not already immersed into a liquidenvironment.

In some embodiments, the method for removing undesirable material fromwithin a vessel can comprise obtaining endovascular accesspercutaneously or by cut down and introducing a sheath. The thrombectomysystem is then introduced through the sheath into the endovascularspace. The guidewire 50 or the secondary wire 99 is advanced to the clot100 and the flexible shaft 12 is advanced to the clot. In someembodiments, the flexible shaft 12 is advanced over the guidewire 50.The catheter 14 is then advanced over the flexible shaft 12 and/orguidewire 50 to the clot 100. The guidewire 50 can then be removedpartially or totally. The catheter 14 and/or flexible shaft 12 is thenpositioned such that the flexible shaft 12 is fully contained within thecatheter 14. Vacuum is then provided to the aspiration catheter system.The thrombectomy mechanism is the activated while the catheter isstationary or moving longitudinally in the vascular lumen. If secondarywire 99 is used, the catheter is moved longitudinally over the secondarywire 99 while thrombectomy mechanism is active. If proximal occlusionmechanism is used: inflate balloon, then activate thrombectomy. Ifdistal occlusion mechanism is used: inflate balloon, then activatethrombectomy. Distal balloon of filter can be pulled back into catheterbefore, during, or after the thrombectomy enhancing clot-catheterinteraction.

In some embodiments, the completeness of the clot removal can bedetected in real time and the operator will be informed to end thethrombectomy mode in time to minimize blood loss related to thecontinuation of vacuum after vessel recanalization. This can be achievedby: 1) sensing the pressure inside the proximal portion of catheter 14,the telescoping system, the actuator handle, the connecting cord betweenthe vacuum pump and the catheter, and/or the vacuum pump 24, as thepressure inside the aforementioned parts will be of the lowest value thedistal end 15 of catheter 14 is engaged and blocked by the clot 100(maximum vacuum generation) and will increase upon the vascularrecanalization with aspiration of blood through the catheter 14 (vacuumdrop); 2) the torque and force on flexible shaft 12, as flexible shaft12 will experience cutting, friction, contacting forces and torqueswhile macerating and interacting with the clot 100 and clot fragmentsand the force and torque on flexible shaft 12 will drop upon thecomplete removal of the clot 100; 3) the power draw for shaft actuation,as flexible shaft 12 actuation power is positively correlated with theforce and torque on flexible shaft 12 and will drop upon the completeclot removal; 4) the power draw from the vacuum pump 24, as the vacuumpump 24 will consume a higher power when generating a lower pressure incatheter 14 due to the catheter distal tip block and engagement withclot, and the vacuum pump 24 power draw will drop when pressureincreases upon clot removal and blood aspiration through the catheter;5) the electric current in shaft actuation and vacuum pump, as thecurrent is positively correlated with the aforementioned power draw; 6)the acoustic frequency and magnitude produced by the system, as theoperational sound of flexible shaft 12 actuation system and vacuum pumpwill change at different power consumption; and 7) the visual feedbackprovided to the operator upon the identification of blood aspirated intothe canister. Upon detection of the complete clot removal, audio,visual, or haptic feedback can be provided to the operator.

In some embodiments, jamming or stalling of flexible shaft 12 andcomponents of the telescoping system can be monitored in real timeby: 1) the torque and force on flexible shaft 12, as these will increasesignificantly and sharply upon jamming or stalling; 2) the power drawfor shaft actuation, as the power draw is positively correlated withflexible shaft 12 force and torque which will increase upon jamming orstalling; and 3) the electric current in shaft actuation system, as thecurrent is one of the measures for power draw which is positivelycorrelated with power draw and will increase upon jamming or stalling.Upon the detection of the catheter jam/shaft stall, the thrombectomymechanism will be automatically stopped and audio, visual, or hapticfeedback will be provided to the operator. The response to catheterjam/shaft stall can be implemented via mechanical mechanism andelectronic control or the combination of both. The mechanical mechanismto automatically stop the thrombectomy upon detection of the catheterjam or shaft stall includes but not limited to a torque limitedcoupling.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. An apparatus, comprising: an aspiration catheterdefining a lumen, the aspiration catheter coupleable to a vacuum sourceconfigured to apply a vacuum pressure within the lumen, the aspirationcatheter including a distal end disposable within a vessel near athrombus; a flexible shaft disposable within the lumen, the flexibleshaft having a bending stiffness that is greater at a proximal end ofthe flexible shaft and is reduced at a distal end of the flexible shaft;a drive system coupleable to the flexible shaft, the drive systemconfigured to translate the flexible shaft relative to the aspirationcatheter, the drive system further configured to rotate the flexibleshaft when the distal end of the flexible shaft is disposed within thelumen and vacuum pressure is being applied such that the distal end ofthe flexible shaft can reshape the thrombus to enable the thrombus to bedrawn proximally within the lumen, the flexible shaft having sufficienttorsional strength to resist breakage when rotated by the drive system;and a set of one or more seals disposable within or about the drivesystem, the set of one or more seals configured to prevent leakage ofvacuum pressure applied within the lumen.
 2. The apparatus of claim 1,wherein the bending stiffness of the proximal end of the flexible shaftis less than 5000 N·mm², and the bending stiffness of the distal end ofthe flexible shaft is less than 50 N·mm².
 3. The apparatus of claim 10,wherein the flexible shaft has sufficient torsional strength to resistbreakage when rotated by the drive system at a speed greater than 10,000revolutions per minute (RPM).
 4. The apparatus of claim 1, wherein theflexible shaft is formed of a plurality of segments, each segment fromthe plurality of segments having a different bending stiffness with moredistal segments having a lower bending stiffness than more proximalsegments.
 5. The apparatus of claim 1, wherein the distal end of theflexible shaft, when the flexible shaft is rotated, rotates about alongitudinal axis of the flexible shaft and moves orbitally about alongitudinal axis of the aspiration catheter.
 6. An apparatus,comprising: an aspiration catheter defining a lumen, the aspirationcatheter coupleable to a vacuum source configured to apply a vacuumpressure within the lumen, the aspiration catheter including a distalend disposable within a vessel near a thrombus; a flexible shaftdisposable within the lumen, the flexible shaft transitionable between afirst configuration for navigating the distal end of the aspirationcatheter to the thrombus and a second configuration for reshaping thethrombus, the flexible shaft in the first configuration having a distalend disposed distal to the distal end of the aspiration catheter, theflexible shaft in the second configuration having the distal enddisposed proximal to the distal end of the aspiration catheter; and adrive system coupleable to the flexible shaft, the drive systemconfigured to translate the flexible shaft relative to the aspirationcatheter to move the flexible shaft between the first configuration andthe second configuration, the drive system further configured to rotatethe flexible shaft in the second configuration to enable the thrombus tobe drawn proximally within the lumen when vacuum pressure is applied. 7.The apparatus of claim 6, wherein the drive system is configured torotate the flexible shaft in the second configuration at a speed greaterthan 10,000 revolutions per minute (RPM).
 8. The apparatus of claim 7,wherein the drive system is configured to rotate the flexible shaft inthe first configuration at a speed of less than 200 revolutions perminute (RPM).
 9. An apparatus, comprising: an aspiration catheterdefining a first lumen, the aspiration catheter coupleable to a vacuumsource configured to apply a vacuum pressure within the first lumen, theaspiration catheter including a distal end disposable within a vesselnear a thrombus; a flexible shaft disposable within the first lumen, theflexible shaft having a proximal end, a distal end, and a second lumenextending from the proximal end to the distal end, the second lumenconfigured to receive a guidewire, the flexible shaft having a diameterthat decreases or remains constant from the proximal end to the distalend of the flexible shaft; a drive system coupleable to the flexibleshaft, the drive system configured to translate the flexible shaftrelative to the aspiration catheter, the drive system further configuredto rotate the flexible shaft when the distal end of the flexible shaftis disposed within the first lumen and vacuum pressure is being applied,when the flexible shaft is rotated by the drive system, the distal endof the flexible shaft rotating about a longitudinal axis of the flexibleshaft and moving orbitally about a longitudinal axis of the aspirationcatheter to reshape and draw the thrombus into the first lumen; and aset of one or more seals disposable within or about the drive system,the set of one or more seals configured to prevent leakage of vacuumpressure applied within the first lumen.
 10. The apparatus of claim 9,wherein the proximal end of the flexible shaft has an outer diameterthat is greater than the outer diameter of the distal end of theflexible shaft.
 11. The apparatus of claim 10, wherein the outerdiameter of the proximal end of the flexible shaft is between 0.026inches and 0.040 inches, and the outer diameter of the distal end of theflexible shaft is between 0.026 inches and 0.034 inches.
 12. Theapparatus of claim 9, wherein the rotation and the orbital movement ofthe distal end of the flexible shaft further enhances proximal movementof the thrombus within the first lumen by transforming static frictionbetween the thrombus and an inner wall of the aspiration catheter tokinetic friction.
 13. The apparatus of claim 9, wherein the flexibleshaft includes an eccentric mass embedded within the flexible shaft ator near the distal end of the flexible shaft, the eccentric massconfigured to enhance the orbital movement of the distal end of theflexible shaft when the drive system rotates the flexible shaft.
 14. Theapparatus of claim 9, wherein the flexible shaft is transitionable froma linear configuration into a non-linear configuration in which a distalend of the flexible shaft has at least one of an angle or a non-linearshape.
 15. The apparatus of claim 14, wherein the flexible shaft istransitionable from the linear configuration into the non-linearconfiguration after the guidewire is removed from the second lumen ofthe flexible shaft.
 16. The apparatus of claim 9, wherein the flexibleshaft is formed from multiple layers of wound wires.
 17. The apparatusof claim 9, wherein the flexible shaft is formed from wires wound inopposite directions.
 18. The apparatus of claim 9, wherein the flexibleshaft is formed of a plurality of segments, each segment from theplurality of segments having a different stiffness with more distalsegments having a lower stiffness than more proximal segments.
 19. Theapparatus of claim 18, wherein the each segment from the plurality ofsegments further has a different diameter with more distal segmentshaving a smaller diameter than more proximal segments.
 20. The apparatusof claim 18, wherein the plurality of segments includes more than twosegments.
 21. The apparatus of claim 9, wherein the rotation and theorbital movement of the distal end of the flexible shaft generates apressure difference from outside to inside the first lumen of theaspiration catheter to draw the thrombus into the first lumen.
 22. Amethod, comprising: navigating a distal end of an aspiration catheterwithin a vessel to a site including a thrombus; navigating a distal endof a flexible shaft to a location near the site, the flexible shaftincluding at least a portion disposed within a lumen of the aspirationcatheter; positioning the distal end of the flexible shaft proximal tothe distal end of the aspiration catheter and within the lumen of theaspiration catheter; and rotating, after the distal end of the flexibleshaft has been positioned proximal to the distal end of the aspirationcatheter and within the lumen of the aspiration catheter, the flexibleshaft using a drive mechanism coupled to a proximal end of the flexibleshaft to reshape the thrombus and draw the thrombus proximally into thelumen of the aspiration catheter.
 23. The method of claim 22, whereinrotating the flexible shaft to reshape the thrombus includes rotatingthe flexible shaft at a speed greater than 10,000 revolutions per minute(RPM).
 24. The method of claim 23, wherein navigating the distal end ofthe flexible shaft includes at least one of: translating the flexibleshaft using the drive mechanism, or rotating the flexible shaft usingthe drive mechanism at a speed less than 200 revolutions per minute(RPM).
 25. The method of claim 22, wherein the distal end of theaspiration catheter is navigated to the site after the distal end of theflexible shaft is navigated to the location near the site, and thedistal end of the aspiration catheter is navigated over the flexibleshaft to the site.
 26. The method of claim 22, wherein the distal end ofthe aspiration catheter is navigated over a guidewire to the site. 27.The method of claim 22, wherein the flexible shaft defines a lumen thatis configured to receive a guidewire, the flexible shaft being navigatedto the location near the site over the guidewire.
 28. The method ofclaim 27, further comprising: removing the guidewire from the lumen ofthe flexible shaft; and transitioning, after removing the guidewire, theflexible shaft from a linear configuration to a non-linearconfiguration.
 29. The method of claim 28, wherein the flexible shaft inthe non-linear configuration has at least one of an angle or anon-linear shape at the distal end of the flexible shaft.